The US Supreme Court on Monday sided with a Texas state trooper who was sued after he shot and killed a fleeing suspect during a high speed chase, a decision that will make it more difficult to sue police who use deadly force during pursuits.

The Los Angeles Timesreports the justices ruled 8-1 in Mullenix v. Luna (text here) that police officers are immune from lawsuits unless it is “beyond debate” that they acted in a manner that was clearly unreasonable and unjustified.

The court ruled that Texas State Trooper Chadrin Mullenix cannot be held liable for the 2010 death of Israel Leija Jr., who the officer shot from a highway overpass outside Amarillo. Mullenix heard about a high speed pursuit involving Leija on his patrol vehicle’s radio and ignored an order from his commanding officer to stand by and not give chase. Mullenix claimed he shot at the fleeing suspect’s car in an attempt to disable it; instead he killed Leija, whose family then sued.

A federal judge ruled that the case could proceed to a jury trial to determine whether Mullenix acted reasonably when he shot Leija. The US 5th Circuit Court of Appeals subsequently ruled 2-1 that the trooper was not entitled to immunity, a decision later affirmed by the full appeals court in a 9-6 vote. Texas state attorneys appealed that ruling; after six weeks of consideration, the nation’s highest court backed Mullenix, granting him qualified immunity from the lawsuit.

“By the time Mullenix fired, Leija had led police on a 25-mile chase at extremely high speeds, was reportedly intoxicated, had twice threatened to shoot officers and was racing towards an officer’s location,” the court said. “Ultimately, whatever can be said of the wisdom of Mullenix’s choice, this court’s precedents do not place the conclusion that he acted unreasonably in these circumstances beyond debate.”

But in the lone dissent, Justice Sonia Sotomayor wrote that the majority’s decision sanctions “a ‘shoot first, think later’ approach to policing,” which the progressive justice argued “renders the protections of the Fourth Amendment hollow.”

“When Mullenix confronted his superior officer after the shooting, his first words were, ‘How’s that for proactive?’” Sotomayor wrote. “The glib comment… seems to me revealing of the culture this court’s decision supports when it calls it reasonable—or even reasonably reasonable—to use deadly force for no discernible gain and over a supervisor’s express order to ‘stand by.’”

Justice Antonin Scalia and Sotomayor clashed over when the term ‘deadly force’ should be used, with Scalia arguing that “it does not assist analysis to refer to all use of force that happens to kill the arrestee as the application of deadly force.”

While Scalia acknowledged that police officers sometimes use a level of violence that is “sufficient to kill,” the conservative justice asserted that such incidents should not be called “deadly force” unless an officers acts “with the object of harming” a suspect.